This one go plunk

Dave Larrington said:

Well, it's more a sort of metallic click, which occurs when the left

pedal

Quoted message said:

is at what would be bottom dead centre on an upright bike, but is
fully-forward for we Dark-Siders.

It's not the pedal(s), coz I've recently replaced them and it still

does it.

Quoted message said:

Thus it seems most likely to be the crank or the bottom bracket.

It's a 105

Quoted message said:

Octalink job and is the cranks are as tight as I can get them with an
outsize Allen key.

So, does The Panel think its more likely that:

o the BB is shot, or
o the crank(s) are shot, or
o both

It's slowly but surely driving me mad...

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
They came for Dani Behr; I said: "she's over there, behind the

wardrobe".

Take the cranks off, spin the BB to make sure it's smooth. Take the BB
out and ensure the BB shell is faced, mucho grease inside the BB shell
and inside the left BB cup. Grease onto the octalink splines, install
it w/o the little cap on to ensure the splines are lined up. Tighten it
as much as you can, TIGHT!!

If still noise, I donno what it is.

Standing or sitting? Could be the saddle.

Qui si parla Campagnolo said:

Standing or sitting? Could be the saddle.

Bike in question is a recumbent, so that's the one thing which it absolutely
isn't :-)

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
und keine Eie.

:
: It's not the pedal(s), coz I've recently replaced them and it still does
it.
: Thus it seems most likely to be the crank or the bottom bracket. It's a
105
: Octalink job and is the cranks are as tight as I can get them with an
: outsize Allen key.

Last summer, I got caught in a rain shower. Then, a few months later, I
started hearing a noise similar to yours. Finally, I went to have a look at
the bottom bracket. To my surprise, there was rust in there. I speculate
that as the crank went around to one particular spot, it hit the rust. I
cleaned it out really well, lubricated, and re-assembled and the noise
disappeared.

So, I vote for the bottom bracket being the source of the problem.

Pat in TX

Dave Larrington said:

Well, it's more a sort of metallic click, which occurs when the left

pedal

Quoted message said:

is at what would be bottom dead centre on an upright bike, but is
fully-forward for we Dark-Siders.

It's not the pedal(s), coz I've recently replaced them and it still

does it.

Quoted message said:

Thus it seems most likely to be the crank or the bottom bracket.

It's a 105

Quoted message said:

Octalink job and is the cranks are as tight as I can get them with an
outsize Allen key.

So, does The Panel think its more likely that:

o the BB is shot, or
o the crank(s) are shot, or
o both

<<SNIP>>

I vote for Bottom Bracket.

On a side note, did anyone ever produce a composite recumbant? I have
seen the seat tube separate from the BB shell on some Treks. This can
produce the "plunk" you describe, but not on a recumbant.

Good Luck

rsquared

Klaus said:

On a side note, did anyone ever produce a composite recumbant? I

have

Quoted message said:

seen the seat tube separate from the BB shell on some Treks. This

can

Quoted message said:

produce the "plunk" you describe, but not on a recumbant.

What sort of composite? Fiberglass/aluminum? Carbon fiber/Kevlar? Wood?
I've seen recumbents built from all these materials. A little more than
a week ago, I was drooling over a carbon-fiber version of the Challenge
Taifun:
http://www.challengebikes.com/html/index.php?taal=en&selectie=taifun
They claimed a racing weight of about 16 pounds.

"Production" carbon-fiber recumbents are available from a number of
sources, including Calfee: http://calfeedesign.com/stiletto.shtml

Jeff

Dave Larrington said:

Well, it's more a sort of metallic click, which occurs when the left

pedal

Quoted message said:

is at what would be bottom dead centre on an upright bike, but is
fully-forward for we Dark-Siders.

It's not the pedal(s), coz I've recently replaced them and it still

does it.

Quoted message said:

Thus it seems most likely to be the crank or the bottom bracket.

It's a 105

Quoted message said:

Octalink job and is the cranks are as tight as I can get them with an
outsize Allen key.

So, does The Panel think its more likely that:

o the BB is shot, or
o the crank(s) are shot, or
o both

It's slowly but surely driving me mad...

Face it, Legs. You *are* mad. You're so far off the wall, you're
bouncing down the corridor...

Double-check the pedals. I once had a metallic "crink" that I couldn't
track down. It turned out I'd removed and reinstalled the pedals one
too many times, and there wasn't enough grease on the threads. Each
turn of the cranks caused a squeak in the threads enough to drive me
mad, had I not already been there. Remove and reinstall the pedals,
using plenty of grease on the threads.

Also, check the chainring bolts. I've had mine loosen enough to cause
that mystery squeak- it took a complete removal, cleaning, and
reassembly with grease on all threads and contact surfaces before it
quieted down.

The bottom bracket moving in its threads is another possibility-
removal, cleaning, and reassembly with plenty of grease...

Damn... I'm starting to sound like a borken record.

Never mind all that. Irradiate the entire assembly with gamma
radiation. This will kill off any microbes that have taken up residence
in the frame. Obviously, they're annoyed and complaining.

Sincerely yours,

Jeff

Dave Larrington said:

Well, it's more a sort of metallic click, which occurs when the left pedal
is at what would be bottom dead centre on an upright bike, but is
fully-forward for we Dark-Siders.

It's not the pedal(s), coz I've recently replaced them and it still does it.
Thus it seems most likely to be the crank or the bottom bracket. It's a 105
Octalink job and is the cranks are as tight as I can get them with an
outsize Allen key.

So, does The Panel think its more likely that:

o the BB is shot, or
o the crank(s) are shot, or
o both

It's slowly but surely driving me mad...

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
They came for Dani Behr; I said: "she's over there, behind the wardrobe".

I'll vote for the crank as the more likely.

I've broke 5 left cranks over the last 2 years and most gave a high pitched squeaky clunk near max extension for some time before failure. Never broke a BB, so don't know what sound they make. I can't distinguish the sound of a pedal axle approaching failure from a crank (I've broke 2 left ones over the last 9 months)-they sound similar.

I like the idea of swapping the crank with one from another bike and seeing whether the problem goes with the crank to the other bike or remains with the BB. Also, what about the BB shell?

BTW: Anyone have any idea why I only have the left side cranks fail and never a right side crank failure?

Dave Larrington said:

it's more a sort of metallic click, which occurs when the
left pedal is at what would be bottom dead centre on an
upright bike, but is fully-forward for we Dark-Siders.
...
So, does The Panel think its more likely that:

o the BB is shot, or
o the crank(s) are shot, or
o both

I've encountered cyclic noise like that on a number of occasions from
both a loose/cracked crank, and also from a dry/loose BB. The crank
noise tends to be a higher-pitched *click*, and the BB noise tends to be
low, muffled *clunk*, but it's usually hard to tell by listening. My
standard repair is to take the entire crankset apart, clean everything,
inspect everything, and replace the parts that look in any way suspect.
This has failed to eliminate the noise only once, and in that one case,
I attributed the noise to a curse-resistant poltergeist.

--
"There are two ways you can get exercise out of a bicycle:
you can 'overhaul' it, or you can ride it."
-- Jerome K. Jerome, "Three Men on the Bummel" (1900)

I said:

[clicky noise stuff]

The Panel will no doubt be pleased to know that, following the removal and
reinstallation of cranks and b/b, with lashings of ginger beer^w^w grease,
the clickiness of my Speedmachine's transmission is now this: 0. Many
thanks for the suggestions.

Had I remembered to tighten the brake lever pivot bolts a thou while I was
at it, pristine silence would have been completely restored. Bah!

I should also like to note that while it /may/ be possible to use a small
coin to plug the end of an Octalink b/b axle, such that a standard crank
extractor may be used, attempts to do so with a BRITONS' One Penny will
result in a small, but perfectly formed, copper-plated steel bowl and a
resolutely unmoving crank.

Next question: where the hell did I put my sunglasses?

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
It is impossible to eat a banana without looking like a tw*t.

Dave Larrington said:

Next question: where the hell did I put my sunglasses?

I think they're right next to my keys...

--
Dave
dvt at psu dot edu

meb said:

BTW: Anyone have any idea why I only have the left side cranks fail
and never a right side crank failure?

Because I keep breaking right pedals and cranks. Cosmic balance.

Jasper